Pay-off apparatus for winding machine

ABSTRACT

A winding machine has a pay-off unit for unwinding a single- or multiple-end type wire material, a feed bobbin, and an optional take-up unit for rewinding the wire material onto one or more bobbins. The pay-off unit is associated with a wire guide device having a motorized carriage, which can slide along the axis of motion, and has an arm that rotates with respect to the carriage and is equipped with an idler wheel onto which material unwound from the feed bobbin is wound. An angular position sensor detects the inclination of the arm with respect to the carriage and a control unit governs the carriage movements as a function of the signals provided by the sensor. The optional winding unit features at least one take-up device with a gripper to grasp an end of the wire material and actuators to reduce the gripping force of the gripper during winding.

RELATED APPLICATIONS

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 10/842,330, filed May 10, 2004.

This application claims priority under 35 U.S.C. 119(a)-(d) to foreignpatent application number M12003A 000938, filed in Italy on May 9, 2003.

FIELD OF THE INVENTION

This invention concerns winding machines and, in particular, a windingmachine with a pay-off unit for unwinding a single- or multiple-end wirematerial from a feed bobbin.

BACKGROUND

As is known, winding machines divide wire material coming from a feedbobbin, which is generally large-sized, onto smaller bobbins, which arethen used in subsequent manufacturing processes. In the pay-off unit,the wire is unwound from the feed bobbin by passing it over a snubpulley. The pulley is generally stationary and positioned centrally withrespect to the feed bobbin. Thus, while unwinding, the wire moveslaterally, forming a variable angle with the pulley. In some cases, andespecially for high-speed work with multiple-end wire (formed from aplurality of single wires wound together), this situation can lead toundesired crossing, overlapping and twisting, possibly resulting inbreaks.

The known solution for overcoming this problem is to mount the pulley sothat it can freely slide along an axis parallel to the feed bobbin. Thepulley is pulled by the wire and follows the movement of the wireitself. This solution is not however entirely satisfactory, since thefriction resulting from the dragging of the pulley can lead tomalfunctions and breakage of the wire. It is therefore necessary toensure a careful take-up of the wire material (often multiple strand)onto the bobbins in order to prevent kinking, winding defects, etc.,which could negatively influence the subsequent manufacturing processes.

Known winding units provide take-up devices in which a strand of thewire is grasped by a gripper positioned at one end of the bobbin to befilled. Once the end of the wire is grasped, the rotation of the bobbincauses the wire to wind onto that same bobbin. However, this creates theso-called “bridge effect” problem: the section of wire extending betweenthe gripper and the initial turns wound on the bobbin quill sticks outfrom the quill, as it is under tension by the flange of the bobbin.Consequently, some turns are wound onto the raised section of wireinstead of directly onto the bobbin's quill, causing a bulge in thewinding that can cause problems in subsequent manufacturing processes.Machines of the prior art do not offer a satisfactory solution to thisproblem.

SUMMARY

One of the objectives of this invention is therefore to provide awinding machine that resolves the aforementioned problems, runningefficiently even at high operating speeds and preventing defects duringthe unwinding and winding of the bobbins.

The present invention is a winding machine having a pay-off unit forunwinding single- or multiple-end wire material from a feed bobbin and awire guide device for guiding the unwound material from the feed bobbinto an outlet of the pay-off unit. The wire guide device has a motorizedcarriage which can slide along an axis of motion and bears an idlerwheel on which the material unwound from the feed bobbin is wound, asensor means to detect the slope of the material between the feed bobbinand the idler wheel, and a control unit to control the movement of thecarriage as a function of the signals supplied by the sensor means. Thewinding machine according to the invention makes it possible for thewire material to be very efficiently unwound from the feed bobbin,preventing defects and breaks, even at high operating speeds.

According to a preferred embodiment, the present invention has at leastone take-up device for wire material onto a bobbin, the take-up devicecomprising a gripper device for gripping a strand of the material and tohold the strand while the material is wound onto the bobbin. The machineof this embodiment further has actuator devices to reduce the grippingforce of the gripper devices on the strand while the material winds ontothe bobbin and holds the strand with less gripping force than theinitial gripping force. This embodiment makes it possible to preventdefects in the take-up unit even in the bobbin formation phase,precluding, in particular, the onset of the so-called “bridge effect”.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of this invention will becomeobvious from the following description of a non-limiting embodiment,with reference to attached illustrated drawings, wherein:

FIG. 1 is a schematic view of an embodiment of a winding machine inaccordance with the present invention;

FIGS. 2 and 3 are a plan view from above and a side view, respectively,with cross sections, of an embodiment of a wire guide device included inthe machine of FIG. 1; and

FIG. 4 is a longitudinal cross-sectional view of an embodiment of atake-up device according to the machine of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows in its entirety a winding machine 1, including a pay-offunit 2, for unwinding a single- or multiple-end wire material 3(metallic for example, though not necessarily so) off of feed bobbin 4,snub and compensation unit 5, and take-up unit 6 for rewinding material3 onto one or more final bobbins. Pay-off unit 2, snub and compensationunit 5, and take-up unit 6 are arranged in series along a path P ofmaterial 3.

Pay-off unit 2 consists of case 10 within which, rotating on specialsupports 11, feed bobbin 4 is mounted, along with motor 12 andtransmission 13 (known) for rotating feed bobbin 4 at a controlled rate,and wire guide device 15 for guiding material 3 unwound from feed bobbin4 to outlet 16 in case 10, toward snub and compensation unit 5.

Referring to FIGS. 2 and 3 as well, wire guide device 15 includesmotorized coupled carriage 17 sliding along guide 18 and moved by motor19. Guide 18 is solidly fastened to rear rim 22 of case 10, facing feedbobbin 4, and extends along an axis A substantially parallel to acentral axis of symmetry of feed bobbin 4 and delineating an axis ofmotion of carriage 17.

Guide 18 consists of a prismatic body 23 featuring a pair of tracks 24arranged on respective faces of body 23, orthogonal to each other, andcoupled with respective sliding members 25 extending from carriage 17.Motor 19 is built into case 10 and is connected to a reduction gear 26.Carriage 17 is connected to motor 19 and dragged along guide 18 by apositive drive belt 27, in a manner well-known in the art and thusneither described nor illustrated for the sake of simplicity.

A straight arm 30 overhangs obliquely from carriage 17 extending towardsfeed bobbin 4, substantially orthogonal to axis A. Arm 30 features aconnecting end 31 hinged to carriage 17 and a free end 32 that supportsan idler wheel 33 onto which material 3 unwound from feed bobbin 4 iswound. Arm 30 is made integral with carriage 17 and rotates with respectto carriage 17. In a preferred embodiment, arm 30 is made integral witha pin 34, which is inserted freely rotating in seat 35 supported bycarriage 17 and extends substantially perpendicular to axis A,delineating an axis of rotation of arm 30 with respect to carriage 17.Carriage 17 has an auxiliary wheel 36, positioned so as to align withidler wheel 33 and mounted directly above connecting end 31 of arm 30.

Wire guide device 15 also consists of sensor means 40 for detecting theinclination of material 3 from feed bobbin 4 and idler wheel 33 andcontrol unit 41 for controlling the movement of carriage 17 as afunction of the signals supplied by sensor means 40. In a preferredembodiment, sensor means 40 has an angular position sensor to detect theinclination of arm 30 with respect to carriage 17. For example, sensor42 maybe a potentiometer (known) joined at connecting end 31 of arm 30to detect the slope of arm 30 with respect to axis A. Sensor 42 istherefore supported by carriage 17 and is connected to rotating pinion43 mounted on carriage 17. Pinion 43 meshes with toothed disk 44(semicircular, for example) which is attached at an upper end of pin 34and rotates integrally with pin 34 and thus with arm 30.

Control unit 41 (known) acts on motor 19 to govern the movement ofcarriage 17 along axis A so as to keep arm 30 substantiallyperpendicular to carriage 17 while material 3 unwinds from feed bobbin4. The electrical connections among the various components of pay-offunit 2 are not shown for simplicity. The functional connection betweencontrol unit 41, sensor 42, and motor 19 is only illustratedschematically in FIG. 2.

Again with reference to FIG. 1, snub and compensation unit 5 is wellknown and is not described in detail for the sake of simplicity. Ingeneral, snub and compensation unit 5 has a plurality of pulleys 47borne by a support 48 and onto which the respective wires or bundles ofwire 49 material 3, taken-off from feed bobbin 4, are wound. Thedistance between pulley pairs 47 varies in order to adjust the workingspeed of pay-off unit 2 to the working speed of take-up unit 6.

Take-up unit 6 has a case 51 and a plurality of bobbin winding devices52 to wind the respective wires or bundles of wires 49 of material 3(originating from snub and compensation unit 5) onto respective bobbins53. Bobbins 53 are drawn from loader 54 and carried to their respectivetake-up devices 52 by a mobile carriage (known and not shown). As shownin FIG. 4, each take-up device 52 has rotating spindle 55, supportedaround an axis of rotation R by case 51 and connected to a motor inknown manner not shown, a bushing 56, fastened to case 51 and withinwhich rotating spindle 55 is housed, and a gripper 57, positioned at afree end of bushing 56 and having support 58 for an empty bobbin 53 tobe filled. Gripper 57 has a mobile element 61 that cooperates whenclosed with its counterpart member 62. Mobile element 61 and counterpartmember 62 delineate the respective jaws of gripper 57 and slide one overthe other along axis R to tighten an end 63 of material 3 (one wire or abundle of wires 49) between mobile element 61 and counterpart member 62in order to hold end 63 while material 3 is winding onto bobbin 53. Atrest, mobile element 61 is kept detached from counterpart member 62 bythe action of a return spring 64.

Bushing 56 is provided internally with a substantially cylindrical seat65 in which rotating spindle 55 is housed, supported by bearings 66.Bushing 56 is fastened to a frame 67, which is in turn fastened to case51.

Mobile element 61 is composed of two tubular telescopic components 71,72, radially fitting one within the other, coupled together and slidingone over the other along axis R. Tubular telescoping component 71 fitsradially over the outside of bushing 56 and slides along axis R withrespect to bushing 56. Frame 67 bears a mechanism 73 to regulate theaxial movement of telescoping component 71 with respect to bushing 56.Mechanism 73 has a small piston 74 a that can slide in a seat formed inframe 67 and terminates with a stopper cap 74 b and an actuator 74 c (ofany known type and shown only schematically in FIG. 4). Stopper cap 74 bcooperates axially, abutting against flange 75 on a radius external totelescoping component 71, in order to provide telescoping component 71with a predetermined and adjustable axial travel distance. Telescopingcomponent 71 is coupled to bushing 56 by inserting two mutuallyconcentric 0-rings 76. Telescoping component 71 is equipped with oneshoulder 77 within the internal radius, facing a shoulder 78 formed onthe external lateral surface of bushing 56 to delineate an annular 79compartment positioned between O-rings 76. Compartment 79 is connectedthrough a conduit 80 to a pneumatic actuator 81 (known and onlyschematically represented in FIG. 4). Telescoping component 71 also hasa cylindrical end portion 82 which houses sliding tubular telescopingcomponent 72.

Telescoping component 72 overhangs axially extending from telescopingcomponent 71 and has a portion 83 that inserts sleeve-like into portion82 of telescoping component 71 and an annular 84 head axially integratedto and rotates around portion 83 by. means of bearings 85. Portion 83 isloaded by a spring actuator 91 composed of a plurality of springs 92arranged in parallel and circumferentially along an end rim 93 ofportion 83 and positioned between end rim 93 and a stop 94 within theradius formed by telescoping component 71.

Telescoping component 72 slides with respect to telescoping component 71along the axis R from a retracted position to an extracted position. Alocking screw 95, composed of a radial peg fastened to telescopingcomponent 71 and housed in a long groove 96 formed along telescopingcomponent 72 parallel to axis R, limits the axial travel distance oftelescoping component 72 with respect to telescoping component 71 to apre-determined value. Springs 92 tend to move telescoping component 72away from telescoping component 71 and to keep telescoping component 72in the extracted position.

Head 84 features a substantially planar frontal striking surface 98 thatcooperates with a surface 99 of counterpart member 62. Counterpartmember 62 is integrally connected to and rotates around spindle 55 andis provided with a support 58 for empty bobbin 53 to be filled which,once inserted on support 58, rotates integrally with support 58 andtherefore rotates together with the counterpart member 62 and then withspindle 55.

Actuator 81 is controlled by a control unit 100 (known and onlyschematically shown in FIGS. 1 and 4), which also commands actuator 74c. Actuators 81, 91 act on gripper 57 to reduce the grasping force ofgripper 57 on strand 63 while material 3 is being wound onto bobbin 53and hold strand 63 with a lesser grasping force than the initialgripping force, bringing gripper 57 from an initial operationalcondition, in which gripper 57 holds strand 63 with a pre-determinedgripping force, to a second operational condition, in which gripper 57holds strand 63 with a gripping force less than the pre-determinedgripping force. Actuators 81, 91 may be any suitable such device knownin the art including, but not limited to, pneumatic and spring-loadeddevices.

In the non-limiting embodiment referred to herein, actuators 81, 91 acton telescoping components 71 and 72, respectively, and may be activatedselectively using control unit 100, to exert a primary and secondarygripping force, respectively, on strand 63. The secondary gripping forceis less than the initial gripping force, has a non-zero value, and issubstantially equal to the force exerted on strand 63 from the windingof material onto bobbin 53.

Machine 1 operates as follows: Feed bobbin 4 is positioned in case 10 ofpay-off unit 2. One or more strands 63 of material 3 wound onto feedbobbin 4 are positioned on idler wheel 33 and on auxiliary wheel 36 ofwire guide device 15. They then pass onto pulley 47 of snub andcompensation unit 5 and are finally fastened onto their respectivewinding devices 52, being gripped with respective grippers 57.

As material 3 is unwound from feed bobbin 4, it moves in parallel to thesame axis of feed bobbin 4. Arm 30 tends to follow this movement,inclining with respect to carriage 17. Sensor 42 detects the angulardisplacement of arm 30 with respect to carriage 17, a displacement thatis also a measure of the slope of material 3 with respect to feed bobbin4. The signal detected by sensor 42 goes to control unit 41, whichgoverns motor 19 moving carriage 17 so as to keep arm 30 substantiallyperpendicular to axis A at all times.

As regards take-up unit 6, the operator places each strand 63 betweenmember 61 and the counterpart member 62 of gripper 57. Control unit 100(actuated by the operator) then governs the activation of pneumaticactuator 81, which acts on telescoping component 71 to securely griptelescoping component 71 against counterpart member 62 with theintervention of telescoping component 72. The emission of pressurizedfluid in compartment 79 in fact causes the displacement of the entiremobile member 61 along axis R and brings gripper 57 to the operationalcondition in which gripper 57 holds strand 63 with a relatively high,pre-determined gripping force. Telescoping component 72 is essentiallyclamped against counterpart member 62 by the action of pneumaticactuator 81. Control unit 100 then activates mechanism 73, governing theadvance of the small piston 74 a driving the stopper cap 74 b to abutagainst flange 75.

The take-up onto each bobbin 53 then commences. After a few turns, aninitial section of the wire (or bundle of wires) 49 stretches fromgripper 57 and the turns themselves. At this point, control unit 100automatically controls the loosening of the gripping force of gripper57. To do so, control unit 100 releases actuator 81, which then ceasesto exert its action on mobile member 61. Despite the action of returnspring 64, telescoping component 71 is blocked by stopper cap 74 bcooperating with flange 75. Telescoping component 72 is no longer drivenby the action of actuator 81 but is pushed by springs 92 and istherefore kept abutted against counterpart member 62 by the force ofsprings 92 alone. The force of springs 92 is less than the force exertedby actuator 81 and of a magnitude that allows the slipping of wire 49 ingripper 57. In this way, wire 49 flattens on the bobbin's quill 53without causing bulging. When the whole initial section of the wire 49is wound beneath the turns being formed, control unit 100 againactivates actuator 81, restoring the initial gripping force that ismaintained until the end of the winding process, and mechanism 73,retracting the small piston 74 a.

Each of the various embodiments described above may be combined withother described embodiments in order to provide multiple features.Furthermore, while the foregoing describes a number of separateembodiments of the apparatus and method of the present invention, whathas been described herein is merely illustrative of the application ofthe principles of the present invention. Other arrangements, methods,modifications, and substitutions by one of ordinary skill in the art aretherefore also considered to be within the scope of the presentinvention, which is not to be limited except by the claims that follow.

1. A winding machine comprising: a pay-off unit for unwinding single- ormultiple-end wire material from a feed bobbin; and a wire guide devicefor guiding the unwound material from the feed bobbin to an outlet ofthe pay-off unit, the wire guide device comprising: a motorizedcarriage, which can slide along an axis of motion; an arm bearing anidler wheel on which the material unwound from the feed bobbin is wound,the arm being rotatably attached to the carriage and rotating angularlyalong the axis of motion of the carriage; sensor means to detect theslope of the material between the feed bobbin and the idler wheel; and acontrol unit to control the movement of the carriage as a function ofthe signals supplied by the sensor means.
 2. A machine according toclaim 1, wherein the sensor means comprises an angular position sensorto detect the slope of the arm with respect to the carriage.
 3. Amachine according to claim 2, wherein the control unit governs themovement of the carriage along the axis of motion to keep the armsubstantially perpendicular to the axis of motion while the wirematerial is being unwound from the bobbin.
 4. A machine according toclaim 3, wherein the arm extends cantilever-like from the carriagesubstantially perpendicular to the axis of motion and features aconnecting end hinged to the carriage and a free end bearing the idlerwheel.
 5. A machine according to claim 4, wherein the sensor is apotentiometer associated with the connecting end of the arm to detectthe slope of the arm with respect to the axis of motion.
 6. A machineaccording to claim 1, further comprising: at least one take-up devicefor winding wire material onto a bobbin, the take-up device comprising:at least one gripper device for gripping a strand of the material and tohold said strand while the material is wound onto the bobbin; and atleast one actuator device to reduce the gripping force of the gripperdevices on said strand while the material winds onto the bobbin andholds said strand with less of a gripping force than the initialgripping force.
 7. A machine according to claim 6, wherein the actuatordevice acts on the gripper device to bring the gripper device from aninitial operational condition, in which the gripper device holds ontosaid strand with a pre-determined gripping force, to a secondoperational condition, in which the gripper device retains said strandwith a gripping force less than said pre-determined gripping force.
 8. Amachine according to claim 7, wherein the take-up device comprises botha primary and a secondary actuator device that may be activatedselectively to exert an initial and secondary gripping force, in thatorder, less than the initial gripping force, on said strand.
 9. Amachine according to claim 8, wherein said secondary gripping force hasa value other than zero and is substantially equal to the force exertedon said strand from the winding of the wire material onto the bobbin.10. A machine according to one of claim 6, wherein the gripper devicecomprises a moving member that cooperates when closed with a counterpartmember to grip said strand between the moving member and the counterpartmember, said moving member comprising a primary and a secondary elementthat are coupled and which slide over each other along an axis.
 11. Amachine according to claim 8, wherein the primary actuator device is apneumatic actuator device and the secondary actuator device is aspring-loaded actuator device.
 12. A machine according to claim 8,wherein the secondary element extends axially and cantilever-like fromthe primary element and features an abutting surface cooperating withthe counterpart member and the primary actuator device acts on saidprimary element to firmly grip the primary element against thecounterpart member with the intervention of the secondary element.
 13. Amachine according to claim 12, wherein the secondary element slides withrespect to the primary element for a pre-determined travel distancebetween a retracted position and an extracted position and is propelledby a an elastic device located between the primary and secondaryelements to keep the secondary element in said extracted position.
 14. Amachine according to claim 10, wherein the primary element is supportedby a frame and can slide along said axis with respect to the frame andthe take-up device comprises a mechanism to regulate said axial traveldistance for the element with respect to the frame to provide theprimary element with a pre-determined and adjustable axial traveldistance.
 15. A machine according to one of the claim 7, wherein theactuator devices are controlled by a second control unit.
 16. A pay-offunit for single- or multiple-end wire material from a feed bobbin,comprising: a feed-bobbin support device and a wire guide device toguide the unwound wire material from the feed bobbin to an outlet of thepay-off unit, the wire guide device comprising: a motorized carriagethat can slide along an axis of motion; an arm bearing an idler wheel onwhich the material unwound from the feed bobbin is wound, the arm beingrotatably attached to the carriage and rotating angularly along the axisof motion of the carriage; sensor means to detect the slope of thematerial between the feed bobbin and the idler wheel; and a control unitto control the movement of the carriage as a function of the signalssupplied by the sensor means.
 17. A machine according to claim 16,wherein the sensor means comprises an angular position sensor to detectthe slope of the arm with respect to the carriage.
 18. A machineaccording to claim 17, wherein the control unit governs the movement ofthe carriage along the axis of motion to keep the arm substantiallyperpendicular to the axis of motion while the wire material is beingunwound from the bobbin.
 19. A machine according to claim 18, whereinthe arm extends cantilever-like from the carriage substantiallyperpendicular to the axis of motion and features a connecting end hingedto the carriage and a free end bearing the idler wheel.
 20. A machineaccording to claim 19, wherein the sensor is a potentiometer associatedwith the connecting end of the arm to detect the slope of the arm withrespect to the axis of motion.